Am I missing something? (stored energy U=.5QV)

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In summary, the conversation discusses a problem involving charge, potential difference, and distance in a capacitor. The question asks for the energy stored in the capacitor, which the speaker calculates using the formula U=.5QV but does not use the distance constant. They question whether they missed something in their calculation and note that data is usually provided for a reason.
  • #1
runran
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So there's this problem where they provide charge on each plate of .02E-9 Coulombs with a potential difference of 240 V. Parallel plates separated by .0004m air. Asks for energy stored in capacitator. I used U=.5QV equation to get 2.4E-6 J but didn't use the .0004 constant at all. Did I miss something in what calculation I'm supposed to be doing? Usually data isn't provided in a problem unless it's supposed to be used, but I can't think of how I would need that. Thank you.
 
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  • #2
runran said:
So there's this problem where they provide charge on each plate of .02E-9 Coulombs with a potential difference of 240 V. Parallel plates separated by .0004m air. Asks for energy stored in capacitator. I used U=.5QV equation to get 2.4E-6 J but didn't use the .0004 constant at all. Did I miss something in what calculation I'm supposed to be doing? Usually data isn't provided in a problem unless it's supposed to be used, but I can't think of how I would need that. Thank you.

Your logic is correct, however you calculations are not. The energy stored is by my calculations is 2.4 x 10-9 J.

~H
 
  • #3
Woops, meant to put Q as .02E-6 c
But thanks Hootenanny for the reassurance that the solution is okay.

A cookie for you (::)
 
  • #4
runran said:
A cookie for you (::)

Why thank you old chap :biggrin:

~H
 

FAQ: Am I missing something? (stored energy U=.5QV)

What is "Am I missing something?"

"Am I missing something?" refers to a question about whether a person is overlooking or forgetting something important or significant.

What does "stored energy U=.5QV" mean?

"Stored energy U=.5QV" is an equation that represents the amount of potential energy stored in a system, where U is the energy, Q is the charge, and V is the voltage.

How is this equation used in science?

This equation is commonly used in physics and engineering to calculate the potential energy stored in a system, such as a capacitor or a battery. It is also used to understand the relationship between charge, voltage, and energy in electrical systems.

What are some real-world applications of this equation?

This equation is used in various real-world applications, such as in the design and operation of electronic devices, energy storage systems, and power grids. It is also used in understanding the behavior of lightning strikes and the charging of batteries.

What would happen if we ignore or forget about this equation?

If we ignore or forget about this equation, we may not fully understand the potential energy stored in a system, which can lead to incorrect calculations and predictions. It is important to consider this equation when dealing with electrical systems to ensure accurate and efficient use of energy.

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